Silicon steel performance requirements
Silicon steel is a kind of soft magnetic material. It is mainly used to manufacture the iron cores of motors and transformers. The performance requirements for silicon steel mainly include iron loss, magnetic induction intensity, magnetic anisotropy, magnetic aging, brittleness, etc. The smelting process of silicon steel is relatively complex. Other steel types are more complex and require precise process technology in various aspects such as refining, converter, RH vacuum, and continuous casting.
Silicon steel is a type of soft magnetic material with a silicon content in the range of 1.0% to 4.5%. It is mainly used to manufacture cores of motors and transformers, ballasts in fluorescent lamps, magnetic switches and relays, magnetic shields and magnets in high-energy accelerators. etc., the performance requirements of silicon steel are as follows:
(1) Low iron loss. Because high iron loss will increase power loss, the main function of adding silicon to steel is to reduce iron loss; reducing sulfur content is beneficial to reducing iron loss; appropriately increasing the phosphorus content in steel is beneficial to reducing iron loss.
(2) The magnetic induction intensity is high, which can reduce the iron core excitation current (no-load current), reduce the copper loss caused by wire electricity and the iron core iron loss, and save electricity.
(3) Requirements for magnetic anisotropy. When the motor works in a running state, the silicon steel is required to be magnetically isotropic and made of non-oriented silicon steel. The transformer works in a static state and is made of cold-rolled oriented silicon steel.
(4) Magnetic timeliness is small. The phenomenon that the magnetic properties of the iron core change with time is called magnetic aging. Magnetic aging is mainly caused by the precipitation of fine carbides and nitrides from supersaturated carbon and nitrogen in steel. Therefore, the carbon content in high-quality non-oriented silicon steel should be less than 0.0035%, and the nitrogen content should be less than 0.005%.
(5) Low brittleness. Silicon steel sheets must be stamped and formed when making iron cores, and the punching performance must be good; if the steel is brittle, it will reduce the yield and affect the life of the die. Sulfur is not only harmful to magnetism, but also makes steel thermally brittle and should be reduced as much as possible.
In addition, the surface of the silicon steel sheet should be smooth and flat, the uniform thickness deviation should be small, and the insulation film should be good.